Oxygenation and cerebral perfusion pressure improved in the prone position

Background: Treatment of patients in the prone position is a well-established method to improve oxygenation in general intensive care unit (ICU) practice. This method is rarely used in a neurosurgical ICU, considering the risk of intracranial hypertension. The aim of this study was to analyse the effect of prone position on intracranial pressure (ICP), cerebral perfusion pressure (CPP) and systemic oxygenation in patients with reduced intracranial compliance. We hypothesize that the beneficial effects of prone position can outweigh the hazardous effects on the intracranial pressure. Methods: Eight patients with traumatic brain injury or subarachnoid hemorrhage (SAH) were studied in the supine and prone posture. Hemodynamics, arterial oxygenation, respiratory mechanics, ICP and CPP were continuously measured. Results: A significant improvement in PaO2 was observed in the prone position, from 12.6 +/- 1.4 kPa to 15.7 +/- 3.2 kPa (P = 0.02). Both intracranial pressure and mean arterial pressure increased in the prone position, from 12 +/- 6 to 15 +/- 4 mmHg (P = 0.03) and from 78 +/- 8 to 88 +/- 8 mmHg (P = 0.005), respectively. Arterial pressure increased to a greater extent than ICP, resulting in improved CPP, from 66 +/- 7 to 73 +/- 8 mmHg (P = 0.03) in the prone position. Conclusions: The prone position can be used to improve the oxygenation as well as CPP in patients with traumatic brain injury or SAH. However, this method results in raised ICP, and should be used cautiously in patients with reduced intracranial compliance.